Creating a site backup may fail with an error message, but the backup file is still successfully created

Summary

• Generating a site backup may result in an error, with the following message:

  Export error

  Internal error: DEAD
  But don't worry, we'll fix it for you!
  You just need to contact Atlassian support and paste in this error message, timestamp and your instance details.

Environment

• Backup Manager

Steps to Reproduce

1. Navigate to Administration area;
2. Access Backup Manager;
3. Click Create Backup button;

Expected Results

• Backup file to be generated as expected

Actual Results

• Even though the file is correctly created the user is shown the following messsage

  Export error

  Internal error: DEAD
  But don't worry, we'll fix it for you!
  You just need to contact Atlassian support and paste in this error message, timestamp and your instance details.
  Timestamp: XXXXXXXXXX

• This error seems intermittent

Workaround

Currently there is no known workaround for this behavior.
However Checking the Backup Manager page later may display the generated file.